Electrical stimulation of nerves or its branches is known to be effective in the treatment of a variety of neurological disorders in living beings spanning from treatment of incontinence to gait disorders.
For treating gait disorders, especially correcting drop-foot, electrodes are placed in the proximity of the peroneal nerve or its branches. A pulse generator connected to the electrode generates a pattern of pulses to stimulate the nerve which will cause the foot dorsiflexor muscles to contract. Thus the foot will be lifted and it will be possible for the patient to swing the leg in a more natural manner. An example of a system for correction of drop-foot is known from U.S. Pat. No. 7,403,821 B2 to Neurodan A/S. The document covers the medical aspects and examples of various preferred embodiments are disclosed. For the triggering of the electrical stimulation of the nerve, according to the wanted reaction of the foot, the use of a foot switch is disclosed. Both the heel-off and heel-strike can be detected and used for input to the pulse generator in order to calculate and initiate the appropriate pulse pattern to be fed to the electrode. The foot switch can be connected to the pulse generator with electrical wires or the foot switch can include a wireless transmitter module for communicating the pulse generator. For the interface between the pulse generator and the electrode the system comprises an inductive link, an antenna to be mounted on the skin of the patient and a counterpart in form of an implantable antenna adapted to be implanted in the thigh of the patient. The pulse generator is equipped with a battery, primary or rechargeable, capable of supplying the system with a source of electrical energy. If the battery is rechargeable, the system is equipped with a connector for attaching a power supply.
Of special concern when designing systems to be used by hemiplegic patients suffering from a stroke is that the system should be easy to use and maintain. It should be possible to operate the device with one hand alone. Thus a disadvantage can be seen in that the system features connectors to be plugged in order to assemble the system or recharge the device. Plugging and unplugging connectors can be a challenging task for hemiplegic patients. Another aspect is patient safety, where charging the battery should be prevented when the system is carrying out electrical stimulation of nerves.
There seems to be room for improvements in the design for providing a system that is simpler to use by hemiplegic patients and in addition avoids the situation where charging and electrical stimulation is carried out simultaneously.